During metal-cutting machining of surfaces these surfaces are frequently covered with stick-on foils to protect the surface from the effects of foreign bodies, i.e. from damage through tools or machining residues, with these foils having to be removed again after the surface has been machined. Foils which are coated with an adhesive are also used to protect the surface when transporting component parts having large surface areas, such as for example the surfaces of refined steel plates or lacquered new vehicles. The foils can consist of different materials. In particular the protective foils are made from polyolefins, i.e. polyethylene (PE) or polypropylene (PP). Polyolefins have an elongation at break of more than 200%.
Protective foils of this kind are also used in aircraft construction throughout the entire structural manufacturing process in order to prevent damage to the exterior skin of the aircraft body during its machining. These machining processes are in particular drilling into the exterior skin for fitting connecting elements.
The said commercially available protective foils have the drawback however that when drilling, for example into the aircraft exterior skin, the foils become loose in the area of the exterior skin around the bore holes so that a tent-like cavity can form between the foil and the exterior skin of the aircraft. The transition from the protective foil lying directly thereon to the detached protective foil is blurred, a precisely defined border line between the two areas does not exist. When the foil becomes detached its protective action around the edge of the bore is limited or becomes completely lost. Furthermore the detached foil can become lodged in the channels of a drill thereby obstructing the forward propulsion of the drill. Precision drilling is then no longer possible or only possible with restricted conditions. Residues of this kind can also remain when tearing off the foil so that they become jammed between a component part and a connecting element for connecting two component parts and thus can lead to an unstable connection.